This invention comprehends both method and apparatus for cleaning wounds with an ultrasonic cleaner and for surgically preparing bones to receive a prosthesis.
Ultrasonic cleaners are known to those skilled in the art as evidenced by the ultrasonically agitated liquid contained within a vat and used for cleaning jewelry. The jewelry is deposited directly into the vat where it is surrounded by the cleaning liquid which is agitated by ultrasonic energy. Rare and expensive jewelry can be cleaned safely by utilizing this unique cleaning method. The medical profession has discovered that a wounded hand, for example, can be placed into an ultrasonic cleaner, similar to the one used for cleaning jewelry, and that suitable detergents and antibiotics can be added to the liquid contained within the vat, to thereby clean the wound in a safe and remarkable manner.
This invention comprehends preparation of a joint whereby joint replacement with a prosthesis can be carried out in a more sophisticated manner than has heretofore been possible. For example, in substituting a prosthesis for a hip joint, the acetabulum or hip socket is reamed out down to healthy bleeding bone. The head of the femur or the hip joint ball is removed by cutting across the bone at the base of the neck, thus exposing the medullary cavity of the femur or thigh bone. The medullary canal is then reamed out with varying size reamers to fit the stem of the prosthesis that is to be used to supply the artificial ball for the ball and socket joint. Once the bed has been prepared, it is necessary to have a completely clean and dry field for use of the methyl methacrylate cement that is ordinarily used to hold the prosthetic components in place.
At the present time, there is not a completely satisfactory method available for use in cleaning out either the acetabular fossa or the medullary canal or femur. Various methods for achieving this operation have been used including irrigation, packing with sponges, and other similar methods, but most of these methods are not entirely satisfactory.
The present invention supplies a solution to this problem in that both the medullary canal of the bone and the acetabular hip joint socket can be cleaned out with a foam that is created by passing a solution of saline containing antibiotics through the central core of an ultrasound transducer resulting in a cavitation of the solution with the formation of a froth which has a tremendous and unexpected cleaning effect. The unusual cleaning affect of this ultrasound created froth is brought about by a mechanical cleansing action wherein transient energy from an ultrasound generator is imparted into a liquid and the liquid is placed into direct contact with the surface of the wound or bone, whereupon, as the stored energy is dissipated it cavitates the liquid while the liquid is in intimate contact with the prepared bone surface, for example, and thereby creates a highly desirable release of energy. This results in the attainment of several different desirable cleaning actions including the direct transference of energy directly to the wound surface as well as the release of energy as small bubbles are created and subsequently ruptured and the transfer of the surface tension energy to mechanically clean the surface of the bone. The apparatus further includes a small tube which is attached and runs down past the ultrasound nozzle so that it can be used to periodically flush out the unwanted debris which has been loosened by the ultrasonic foam.
In the cleansing of the acetabulum (hip socket) an attachment is provided which has a mushroom type configuration with small openings in it that will allow the ultrasonic created froth to act on the raw bleeding bone and thereby mechanically cleanse the surfaces of the bone in a similar manner. Irrigation can be done periodically with a syringe since the acetabulum is usually easily exposed. The same mechanism works for preparation of the bone for insertion of the components of the artificial knee joint replacement, or any other instances in which it is necessary to use methyl methacrylate cement. In some instances in which "pathologic" fractures occur through malignant tumor areas, the use of methyl methacrylate cement has been approved for use with some type of metallic internal fixation in order to secure solidarity of fixation of these fractures. In these instances, of course, the area in which the methacrylate cement is to be inserted must be completely clean and dry. These requirements are easily accomplished by the ultrasonic wound cleaner.
Another use of the present invention is that of a wound cleaner in acute trauma or in the treatment of dirty wounds. By removing the attachments used in carrying out the above method and allowing the ultrasonic created froth to emerge from the collecting chamber directly, the wound can be cleansed by moving or rubbing the instrument back and forth across the open area of the wound cavity and allowing the bubbles of the froth to come in contact with the structures lying in the depths of the open wound. This will be much better technically than local irrigation of the wound with syringes and certainly will be much kinder to tissue than the use of high pressure pumps which are now ordinarily employed for this particular need.
The ultrasonic wound cleaner of this invention is also useful in the emergency room where, on many occasions, less critical but nevertheless dirty and contaminated wounds need to be treated.